The use of navigation systems to provide users with routes from one point to another point, such as those used in automobiles and mapping websites, is widespread. The use of navigation systems on cell phones and PDAs is one of the fastest growth application segments. Navigation systems are also available that are capable of calculating the shortest route for the user. Some navigation systems allow the user to specify route parameters like “avoid highways” and then present the user with a route that avoids highways.
Most navigation systems use static information, such as maps, to generate route and direction information. However, techniques are emerging for incorporating dynamic data into routing. For example, an article entitled “Car Pooling With GIS Map Server and Web Services,” by Muzaffer Dogru, Department of Information Technology, University of Zurich, Switzerland, Aug. 6, 2004, describes an approach by which “demanders” (people who need a ride to go somewhere) can be matched with “offerers” (people who are able to offer a ride). The demanders and offerers can specify not only the end points of their routes but also via locations, which are locations that each person will pass through along their routes. The purpose is to combine multiple routes from different offerers to enable a demander to travel from one point to another through some desired via locations. The end points and via locations of the demander can be thought of as specifying a route. A match occurs even if one or more offerers will be traveling in a synchronized manner across those via locations so that the demander could hitch a ride with them from point to point.
Although the approach taken by Dogru is an intriguing one, one disadvantage is that Dogru's approach may fail to meet the needs of some users. That is, rather than hitching rides with others to get from one point to another, users may rather know which of a number of proposed routes to get from one point to another they should seriously consider based on the routes of others. Using Dogru's approach, only the future or proposed routes of the offerers would be available for use in such an analysis. An unintended consequence of this approach is that it may compromise the offerers' privacy since their current plans may be revealed to others. In addition, it would be desirable to reinforce which routes the user should take based on long-term past historical data, rather than proposed or future route data.